Tag Archives: extinction

One in Six Species of Wildlife May Be Threatened by Climate Change

Up to one in six animal and plant species could vanish from the face of the Earth as casualties of climate change, according to the latest analysis.

The new study was published on Thursday with the journal Science. If that’s hard news to take, it might get even worse. Mark Urban, who is an ecologist from the University of Connecticut, also suspects that as our planet continues to warm up over the rest of the century, the rate of extinction among species will likely begin to accelerate. The presence of most of these animals is necessary for their habitats to remain stable.

“We have the choice,” he warned in a recent interview. “The world can decide where on that curve they want the future Earth to be.”

As severe as these conclusions made by Dr. Urban’s may be, his estimate appears conservative compared to some other counts taken by his colleagues. The precise number of extinctions “may well be two to three times higher,” according to John J. Wiens, who is an evolutionary biologist at the University of Arizona.

Trends of anthropogenic global warming have increased our planet’s average surface temperature by an average of about 1.5 degrees Fahrenheit since the beginning of the Industrial Revolution, a primary reason that modern geologists have lobbied to change the name of the modern geological record to the Anthropocene Era. People forming societies have not only left a permanent mark on the planet, but have also influenced the evolution and even extinctions of an immeasurable number of species. In response to climate change, many animals have begun shifting their habitats, where they face fresh competition in a new and already established ecosystem.

Back in 2003, Camille Parmesan from the University of Texas alongside Gary Yohe from Wesleyan University decided to analyze the published studies of more than 1,700 different species of plants and animals. They subsequently learned that, on an average, the ranges of these animals have shifted over 3.8 miles each decade towards one of the planet’s poles, another unfortunate side effect of climate change that biologists are currently dealing with.

If these emissions of carbon dioxide and other greenhouse gases – such as the much more lethal methane – continue to increase in our atmosphere, climate researchers maintain that the world may warm by as much as a full eight degrees Fahrenheit. As the Earth’s climate continues to intensify, as scientists fear, a number of these species will no longer be able to establish suitable habitats to sustain life.

The American pika, is one such example. These are hamster-like mammals found on mountain ranges throughout the West. In recent years, however, they have been climbing to higher elevations to build their nests. Since the 1990s, some established pika populations living throughout their southernmost ranges have entirely vanished, a loss that may upset the balance of nature in minute ways that will eventually become more pronounced – predators in the area no longer have pikas as a food source, and regional grasses they used for their nests may now grow unchecked.

Hundreds of studies have come out over the course of the last two decades, all of which have released quite a host of predictions about the number of extinctions that may be the result of global warming. So many have entertained the possibility of a mass extinction, that some naturalists have suggested we are living in what will be the sixth major extinction event, with the depletion of many species over the next two million years. Some have predicted few extinctions, while others have maintained that up to 50 percent of the Earth’s species will be eradicated with the planet’s mounting temperatures.

So why is there such a wide variation? The main reason is because all of these studies take different lifeforms into account. Some scientists have focused their efforts solely on plants throughout the Amazon, whereas other researchers concentrated on butterfly species in Canada. In some of these cases, the researchers applied models that considered only a couple of degrees of warming whereas other studies looked into significantly hotter scenarios. Because the scientists were rarely able to give estimates on how quickly one given species might alter its ranges, in some cases they decided to produce a range of estimates.

In order to establish a clearer picture, Dr. Urban decided he would need to look into every climate extinction model that has ever published. He eliminated any studies in which just a single species was examined, such as reports on the American pika, in order to avoid the possibility that his numbers might end up overly inflated. Studies that look at just one species generally imply that the species in question is already in danger of dying out from climates change.

Dr. Urban ended up doing his analysis on 131 different studies examining plants, amphibians, fish, mammals, reptiles and invertebrates, all of which are spread widely across the planet. His study reanalyzed all of their data.

Overall, Urban found that there are 7.9 percent of the world’s species highly vulnerable to becoming extinct from reasons related to climate change. The estimates which factored low levels of warming yielded significantly less extinctions than the hotter scenarios.

According to his calculation, all it would take is an increase of 3.6 degrees Fahrenheit of just the planet’s surface temperature, and 5.2 percent of species could become extinct. At an increase of 7.7 degrees, 16 percent of species would disappear.

Dr. Urban’s model has projected that this rate of extinctions will not increase steadily, but could actually accelerate if temperatures rose. This could mean not just a mass extinction event, but one that may be on par with the Permian Triassic Extinction, in which 90 percent of life on Earth died out, over a period of just 60,000 years – the deadliest event the planet has ever known. Ocean acidification, a growing concern over the last century, has been established as playing a major role in the Permian Triassic event.

Richard Pearson, a biogeographer from University College London, has referred to the latest meta-analysis as “an important line in the sand that tells us we know enough to see climate change as a major threat to biodiversity and ecosystems.”

But, even Pearson maintained that Dr. Urban is most likely underestimating the exact scale of species extinctions. We tend to think of extinctions as a one day cataclysmic event, but the reality is that they take substantial amounts of time, during which habitats diminish and new populations of other animals are introduced. The latest generation of climate extinction models are more accurate, according to Dr. Pearson: “Sadly, they also produce more dire estimates.”

Dr. Wiens also takes note that the tropics have long been underrepresented when doing climate extinction studies, likely because they probably contain large numbers of species that have not yet been discovered, and the margins of errors are considerable. In Dr. Urban’s meta-analysis of the studies, 78 of them focused on animals living throughout North America and Europe, while there were only seven that came from South America, home of the most unusual and rapidly disappearing ecosystem in the world: the Amazon River basin. However, even when Dr. Urban did a combination of all the data acquired from these South American studies, he learned that approximately 23 percent of species on this continent were at a high vulnerability to extinction. In North America, by comparison, only 5 percent of the species were threatened with extinction.

“What makes this imbalance all the more glaring,” Dr. Wiens said, “is the fact that most of the planet’s species live in tropical forests such as the Amazon. If climate extinction research took tropical diversity into account, the planet’s overall risk would be much higher.” Not only animal life, but much of the Amazon’s plants are specially adapted to the region.

Dr. Urban, however, has acknowledged that his meta-analysis is far from the final word, and hopes that other researchers will continue to pursue the totality of species extinctions, as well as the best possible methods for counting them out. “This is a summary of the best information we have right now,” he said. “As the predictions improve, they will allow conservation biologists to pinpoint the species at greatest risk of extinction and help plan strategies to save them.”

The scientists who create subsequent models may actually be able to draw not only from the data we have on living species, but also from extinct ones as well. How the loss of one species is felt by another is an important question to bear in mind.

In an issue of Science this week, an international team of researchers reported a new and rather unsettling find regarding the nature of ocean extinctions over the last 23 million years.

They discovered that particular groups, such as sea mammals, are actually much more prone to extinctions than other groups whose ancestors reach back several ages, such as the mollusks. Biology can help determine how certain species are put at extra risk. For example, in the case of sea mammals, such extinct species as the Steller’s Sea Cow, they typically produce fewer offspring, giving the species lower odds for survival. Other animals may have a limited range, such as modern day amphibians, which are falling victim to fungal diseases and dying off from the loss of their habitats.

Dr. Pearson has said that in the future, climate extinction models have new factors that they will also need to take into account. “What happens to other species in an ecosystem when a species goes extinct?” he asked. “Its partners in that habitat might risk extinction as well.”

Dr. Urban is also aware that there are many other ways in which scientists can improve climate extinction models. A big thing they should seek to do in the future is calculate the increase of human interaction. Humans too have been forced to migrate due to changes in climate, a problem that will unlikely change in the near future – leading to increases in the populations of cities, but also the need for expanding farms as well as other barriers that humans have set for those species who seek new habitats. Giant salamanders in Asia, for example, have had their habitats disrupted from the establishment of hydroelectric plants in local streams, and are at high risk.

The startling results of his research so far, indicates that new and improved prediction models can’t come too late. “We need to elevate our game,” said Urban.

James Sullivan
James Sullivan is the assistant editor of Brain World Magazine and a contributor to Truth Is Cool and OMNI Reboot. He can usually be found on TVTropes or RationalWiki when not exploiting life and science stories for another blog article.

The Big Extinction Event You Never Heard About

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The entire early history of the Earth itself is one of extreme violence – a series of extreme catastrophic accidents that ultimately shaped it into the habitable form it is today – collisions, volcanoes, earthquakes. Even when the Earth was a habitable place, thriving with life, it was unsafe from mass extinction events, which took place roughly every 50 million years or so. To date, scientists describe a “big five” list of these incredible events, the last one wiping out the last of the non-avian dinosaurs 65 million years ago. While it is sometimes argued that the rapid disappearance of species in the present day is the sixth major extinction event, there actually may have already been one that was considerably overlooked in our distant past.

Today, paleontologists argue that this sixth major extinction event took place 260 million years ago, towards the end of a geological age known as the Capitanian, which predated the major Permian-Triassic extinction event by only about eight million years. A recent study offers up the evidence that there was a massive die-off during this age in the shallow, cool waters near what currently make up modern day Norway. This new discovery, along with the combined earlier evidence of extinctions taking place in tropical waters, suggests that the Capitanian event was a catastrophe of global magnitude.

“It’s the first time we can say this is a true global extinction,” said David Bond, a paleontologist from the University of Hull in the United Kingdom. Bond recently led an international team in a study that has been published online this week through the Geological Society of America Bulletin. As overlooked as it has been, Bond maintains that in its magnitude, this Capitanian event was actually on par with the dinosaur-killing extinction that took place 65 million years ago. “I’d put this up there with it, albeit with slightly less attractive victims,” Bond says.

Not a whole lot of people are aware that the dinosaurs existed in a number of forms, over three different eras (the Triassic, Jurassic, and Cretaceous) with some minor extinction events in between, let alone the Capitanian era. Actual scientific interest in this age first began during the early 1990s, during which paleontologists discovered the evidence for fossil extinctions happening in rock formations across China. These rocks had originally formed on the floor of what was once a shallow tropical sea. Most foraminifera — which are tiny, shelled protozoans, only slightly larger than bacteria — had died out, alongside numerous species of the clamlike brachiopods, which make up some of the most commonly found fossils – shell impressions that can be found near most modern streams.

There is also evidence of a potential trigger to blame for the gradual chain of destruction: a series of ancient volcanic outbursts in China. Afterwards, these volcanoes would congeal into a rock formation known as the Emeishan Traps in southwest China’s Sichuan Province. The hot flowing basalt would give off massive amounts of sulfur and carbon dioxide, which was released into the air, potentially leading to a sudden global chill. The brief cooling period would then be followed by a substantially longer period of global warming. The release of carbon dioxide would have also led to intensified ocean acidification, along with oxygen depletion in the water. Ocean acidification later played a role in the Permian-Triassic event, which only took about 60,000 years to obliterate most species on Earth, and was by far the most deadly that the Earth has ever experienced. Many scientists suspect that a similar massive burst of volcanic activity as the one in Emeishan Falls took place in Siberia, setting off a chain reaction of events that would wipe out over 90 percent of life on Earth.

So why has the Capitanian extinction so overlooked? Little is known, and many have suggested that it was a regional event, or that it may have in fact been just an isolated disaster, a symptom of the trends that would eventually culminate in the much larger Permian extinction. It was only officially recognized as an individual era within the Permian Age in 2001 on the international timescale used by geologists. The newly discovered evidence may dispel some of these reservations about the era. One such piece of the puzzle comes out of Spitsbergen, which is the largest island of the Svalbard archipelago, just off the coast of Norway in the Arctic Ocean. It is there that Bond and his colleagues did an examination of chert rocks. These rocks are the result of silica buildup, a volcanic byproduct which has been produced out of the skeletons from dead sponges. The chert may also contain several species of extinct brachiopods. At the time of the Capitanian event, these rocks would have begun forming within tens of meters of cooler water at midlatitudes. But here it’s not so much what the rocks contain that’s interesting, as what isn’t there. There was a point recorded the rock record when these fossils suddenly disappeared.

“They all drop out,” says study co-author Paul Wignall, who is a paleontologist at the University of Leeds in the United Kingdom. “It’s like a blackout zone and there’s nothing around.” At some point a little further along in the rock record, several of the brachiopod species recovered, according to Wignall. Afterwards, the mollusks begin to take over in sizable numbers, thriving right up until the devastation of the Permian extinction begins, another eight million years after. Right now, the ocean acidification due to anthropogenic climate change is reducing pH levels in the ocean water, affecting numerous species that have evolved at specific pH levels and bleaching coral reefs, a pattern that will disrupt a number of marine ecosystems across the planet. Perhaps 260 million years ago, the situation was not too different. There’s been some even more unsettling news – the discovery of shellfish cooked by the increasing acidity, as the ocean tries to act as a carbon sink, absorbing the record levels of carbon dioxide released into the air.

The research team has actually had a difficult time attributing the latest record to the same moment documented by fossil records throughout China. Isotopic dating systems are too uncertain to provide the researchers with a helpful absolute date. Another standard method of dating – biostratigraphy, which links the timing between the different rock layers by the nature of the fossils they contain. In this instance, it’s the appearance and disappearance of fossilized teeth from small tiny eel-like creatures known as conodonts. However, these also couldn’t be used, because the population had diverged, and different species lived in cool waters from those living in tropical waters. Instead, the team has had to rely on a pattern of similar swings at the levels of different isotopes, something that occurs in both parts of the world where the evidence was found, implying that both Scandinavia and Asia had both experienced alterations in oceanic chemistry around the same time.

The imprecise dating may actually be a part of the problem, according to Matthew Clapham, who works as a paleontologist at the University of California, Santa Cruz. He did not participate in the study but thinks that the events dated by the study team may have actually taken place a bit more recently — happening only about 255 million years ago. “They’ve definitely identified a real event, which is really interesting,” he agrees. “Their age model is less convincing.” He also put their discovery in perspective of some recent work in China, which suggests that the full extent of the Capitanian extinction and its effect on different species may actually tell the opposite story – suggesting that it was not nearly as bad as many paleontologists had originally thought. When it comes to listing extinctions, Clapham thinks that the Capitanian is probably 30th or 40th on the hierarchy but certainly not the sixth. Rather, the new discoveries may have been a symptom of the impending Permian mass extinction.

Bond, however, remains convinced that perhaps one day science books will list the Capitanian as one of the worst extinction events in history. “You have to change a lot of people’s minds,” he said. Right now, he is studying the fossil records of Russia and Greenland that may further support his case that the Capitanian was a global disaster. Clapham, too, would like to see a greater understanding of what was largely an enigmatic stretch in the history of our planet. “It’s a very mysterious event—it’s an interesting thing to study,” he says.

At the Core of a Prehistoric Meteor: Uncovering the Last Extinction Event

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The Cretaceous-Paleogene Extinction Event. Formerly known as the K-T extinction event, it’s probably the most famous one by far, though there were far deadlier ones millions of years before it. It was triggered by a falling asteroid one summer about 65 million years ago in what is the modern day Yucatan Peninsula, with an impact that drove up forest fires and extreme tidal waves, successfully wiping all non-avian dinosaurs from the face of the Earth. The crater that remains, however, may hold the key to a number of mysteries surrounding this extinction event.

The meteor is believed to have come from the Baptistina family of asteroids that formed some 160 million years ago in a collision, and is now located in the Chicxulub crater of present day Mexico, where scientists have made plans to drill 5,000 feet deep for a new core sample – transporting them between 10 million to 15 million years into the Earth’s past. This will mark the first time that a core is taken from the crater’s center in an offshore expedition. The resulting crater is named after a nearby fishing village.

It was at this same spot five years ago this month that scientists formally endorsed the hypothesis that the Chicxulub meteor was the primary cause of the Cretaceous event, driving the disastrous trends that followed. It is the most recent of the Big Five mass extinction events to take place on Earth over the past 542 million years.

Just last week, an international team of scientists gathered Mérida, Mexico, a town that fits comfortably inside the 125-mile-wide Chicxulub crater, where they discussed their plans for the drilling project, which is slated to commence in the spring of 2016.

After 65 million years of life coming and going, why choose now to begin the investigation? “The Chicxulub impact crater has been a remarkable scientific opportunity for the 20 years since it’s been discovered,” said Sean Gulick, of The University of Texas at Austin’s Institute for Geophysics. Also, for the first time in history, scientists have subsurface images taken of the offshore point of the crater, giving them a pinpoint for where to begin their sampling. Their target is a spot that runs along the crater’s peak ring — a diadem of mountainous structures encompassing the center of the crater.

By extracting a sample here, the researchers are able to obtain a stronger picture of what ancient biological and geological processes were going to work in the seconds after impact.

Scientists suspect that in the event of a large rock crashing into the Earth at an extreme enough velocity, the collision may cause the crust to temporarily function in the same way a liquid would, with a transient crater beginning to form (think of it as the way ripples begin appearing when you throw rocks or stones into a lake, whereas the point where the rocks are thrown in splashes first upwards and then outwards. “We think the peak ring is the record of the material that rebounded and splashed outward,” Gulick told Live Science in an interview.

So far, these ideas are solely based on models, and do not necessarily express what happened. “We’ve never gotten a rock back from a peak ring to know if that’s correct,” Gulick said.

Hopefully, the sample will change that. If this liquid property did in fact happen, the researchers are also interested in any details about conditions weakening the granite of Earth’s crust that enabled it to flow like a liquid, Gulick noted. “We don’t understand that process,” he said.

The meteor signaled the end of not just the dinosaurs, but three-fourths of all species on Earth, many of which have never been seen before, drawing the Cretaceous Period and the entire Mesozoic Era to a close. Immediately following the impact, a dust cloud rose over much of the Earth, so thick it blocked out the sun and took approximately ten years to dissipate. With up to 20 percent less sunlight reaching Earth, most species of plants and phytoplankton began to die out, causing an effect that would echo throughout the food chain, leading to the deaths of many dinosaurs as well as larger sea dwelling animals.

High levels of oxygen present throughout the Cretaceous would likely have prolonged severe forest fires, ones that may have temporarily produced a greenhouse effect after the dust settled, had they been widespread enough, wiping out yet larger numbers of vulnerable species that survived the initial impact. Those lifeforms that survived lived primarily in streams, feeding off of food washing in from land, rather than depending on living plants. Crocodilians, among the closest living relatives of dinosaurs, also survived as scavengers, likely eating little and slowing down their heart rates in order to cope with the sudden, cold temperatures. Most sea life on the ocean floor avoided extinction, as did the first flowering plants.

Another reason, aside from its dramatic impact that the K-P Event is so prominent in the minds of the general public, and for that matter, the minds of scientists, is because the Chicxulub is so far the only impact crater on Earth that has been successfully linked to a massive extinction event. The Permian-Triassic event has largely been attributed to volcanic activity and the resulting acidification of the oceans, which gradually led to the deaths of about 90 percent of life on Earth. These new samples could offer new information regarding the extinction and all that followed after. The newer layers of rock extracted from the sample, may contain traces of life, providing researchers with clues over how long it took for life to return to the perimeter and thrive again, said Gullick.

The project will have a budget of roughly $10 million project and will be a joint collaboration among both the European Consortium for Ocean Research Drilling (part of the International Ocean Discovery Program) as well as the International Continental Scientific Drilling Program.

Gulick and Joanna Morgan, from the Imperial College of London, shall be leading the team of scientists on this expedition.

Could Dark Matter Be Behind Earth’s Extinction Events?

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Earth’s orbit along the Galactic Disc, is a long yet predictable journey that lasts for eons, but not without consequence, as Michael Rampino, a professor of biology at New York University recently observed. Rampino’s newest research, published in the Monthly Notices of the Royal Astronomical Society, believes that these infrequent rotations have coincided with the state of life on Earth.

While we often think of the comet that brought a rather dramatic end to the dinosaurs 65 million years ago when we hear of extinction, it was hardly the first time that many species died out together. Nor was it even remotely the worst. That distinction belongs to the Permian-Triassic extinction event, which occurred 252 million years ago, coinciding with the Galactic Disc rotation, in which 83 percent of all life became extinct – owing to not only volcanic events but ocean acidification and the impact of several meteors. It took approximately 10 million years for much of the life left on Earth to replenish itself. While it took more than one event to make things hostile for life on Earth, Rampino has attributed the increased number of meteoric impacts to a buildup of dark matter, which may upset the orbits of comets and also increase heating at the Earth’s core – igniting volcanic activity, a trend currently being seen in Iceland.

Even the era that paleontologists purport to be the golden age of Dinosaurs – the Jurassic period – in which some of the largest species of sauropods thrived, was preceded by another violent extinction event – the Triassic-Jurassic extinction – taking place 201.3 million years ago. It took about 10,000 years, partially because of increased activity at a massive underwater volcano known as the Central Atlantic Magmatic Province, as well as several meteoric events which took place in Europe. Today, these periods are known by the rock layers they left behind, yet it is clear that each are caused by the same violent reactions in nature and the resulting change in climate.

The Galactic Disc is a region of the Milky Way Galaxy that defines its shape and contains our solar system, amidst a heavy clutter of stars and clouds of cosmic dust and reactive gasses. Yet, surrounding the cluster, is the elusive dark matter, particles which are primarily known because of the remarkable gravity they release, impervious to light and other forms of electromagnetic radiation.

According to prior studies, the Earth makes a rotation around the Galactic Disc once every 250 million years. However, the path is not always circular but wavy, as the Sun and other planets weave their way in and out of the crowded disc at intervals of approximately 30 million years or so. The Cretaceous-Paleocene event also coincides with these patterns.

So why does dark matter in particular seem like the culprit in these occurrences? When comets move through the disc, concentrations of dark matter can sometimes intensify to the point that they begin to throw comets off course, sometimes this instability causes them to collide with the planet, acts that have defined the shape of Earth throughout its history, and also perhaps supplying it with the very amino acids necessary to sustain life. But dark matter has another somewhat more pernicious impact on our planet in a different way, too.

As the Earth is exposed to dark matter on its rotations, Rampino learned that dark matter could essentially build up within the planetary core, producing an intense heat as its particles collide with each other inside. Eventually the heat builds up considerable pressure, leading to mountain building, volcanic eruptions, and even reversals in the planet’s magnetic field. The history of rises and falls in sea levels also shows a peak happening every 30 million years.

The new model of dark matter and its interactions with planets as they move across the Galaxy could significantly impact how we perceive geological and biological development. Already, our current understanding of the Earth’s natural history is one of violent and destructive events. Dark matter could be a critical cause behind it all. Already, in what geologists have petitioned to refer to as the Anthropocene Era (the Age of Humans – due to our species’ shaping of the planet for better or for worse), many other researchers believe we are in the midst of a sixth extinction event – with climbing levels of CO2 adding to the acidification of the ocean each year. Like dark matter, humans have the power to impact the universe too.

To put this all in perspective, Rampino said in his paper: “We are fortunate enough to live on a planet that is ideal for the development of complex life. But the history of Earth is punctuated by large scale extinction events, some of which we struggle to explain. It may be that dark matter — the nature of which is still unclear but which makes up around a quarter of the universe — holds the answer. As well as being important on the largest scales, dark matter may have a direct influence on life on Earth.”